References of "Destain, Marie-France"
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See detailMapping within-field soil variability for precision agriculture using electromagnetic induction
Hanquet, Bernard; Frankinet, Marc; Parez, Vincent et al

in Proceedings of AgEng (2002)

Among the crops production factors, the soil is obviously one of the most important. Therefore, within the context of Precision Agriculture, the spatial variability knowledge of its physical and chemical ... [more ▼]

Among the crops production factors, the soil is obviously one of the most important. Therefore, within the context of Precision Agriculture, the spatial variability knowledge of its physical and chemical properties is essential as a decision support information for cultural operations modulation. The purpose of this study is to assess the capability of electromagnetic induction sensing of apparent electrical conductivity (ECa) for the characterisation of withinfield variability of soil physical and/or chemical properties in the particular soil conditions encountered in our experimental area, namely non-saline deep silty soils. ECa maps were produced on a 7ha field in April 2001, September 2001 and April 2002. Concurrently, an intensive soil survey (112 points) was carried out in February 2001 in order to determine a series of physical, textural and chemical soil parameters. ECa accurately described clay content, and exchangeable K and Ca cations concentrations. [less ▲]

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See detailDevelopment of a multibody model of a sprayer
Ooms, David ULg; Lebeau, Frédéric ULg; Maton, Nicolas et al

in Proceedings of AgEng (2002)

A multibody model of a sprayer boom including the suspension was developed by using ADAMS 11.0 (Mechanical Dynamics). The model was designed with the aim to describe the dynamic behaviour of different ... [more ▼]

A multibody model of a sprayer boom including the suspension was developed by using ADAMS 11.0 (Mechanical Dynamics). The model was designed with the aim to describe the dynamic behaviour of different types of booms and suspensions (double trapezium, trapezium, pendulum, …). This was obtained by creating a general model in which geometrical (dimensions) and mechanical parameters (mass and inertia, friction coefficients, stiffness and damping coefficients of the hinges, …) of the system were easily modified. A graphical interface especially designed authorised this easy modification. The validation of the model was obtained by measuring in real conditions the frame movements as solicitations and the boom movements as responses. The method was applied on a trailed sprayer equipped with a boom of 24 m and a trapezoidal suspension. Good accordance was found between measured and simulated vertical displacements. The model may decrease the development costs of suspension and boom designs. [less ▲]

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See detailEvaluation of tactile sensors in apple firmness measurement
Petit, Catherine; Leemans, Vincent ULg; Kleynen, Olivier et al

in Proceedings of the Conference 'Physical Methods in Agriculture, Appoach to precision and quality' (2001)

The objective of the work consists to develop a non-destructive fruit firmness measurement. The tactile sensor technology was chosen. The force measurement acting between the fruit-sensor as well as the ... [more ▼]

The objective of the work consists to develop a non-destructive fruit firmness measurement. The tactile sensor technology was chosen. The force measurement acting between the fruit-sensor as well as the contact area are coupled with other meaqsurements, like the color of the fruit. The results of the measurements are compared with the firmness reference values (Magness-Taylor test) and also with the acoustic impulse response technique. Several parameters correlated with firmness are proposed. [less ▲]

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See detailDéveloppement de méthodes pour apprécier 'en ligne' la qualité externe de pommes par vision artificielle
Leemans, Vincent ULg; Destain, Marie-France ULg; Magein, Hugo ULg

Book published by Ministère des Classes moyennes et de l'Agriculture - DG6 -Service Recherche subventionnée (2001)

L'ouvrage présente les résultats des recherches effectuées pour mettre au point un système de tri automatisé pour pommes, en fonction des critères de qualité externe, la couleur, la forme et la présence ... [more ▼]

L'ouvrage présente les résultats des recherches effectuées pour mettre au point un système de tri automatisé pour pommes, en fonction des critères de qualité externe, la couleur, la forme et la présence de défauts. [less ▲]

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See detailSensor Data Fusion for the Measurement of Horizontal Sprayer Boom Displacement
Lebeau, Frédéric ULg; Destain, Marie-France ULg

Conference (2000, September 14)

The measurement of horizontal sprayer boom movements is an important parameter for the simulation of repartition generated by a sprayer in the dynamic environment of agricultural fields. The existing ... [more ▼]

The measurement of horizontal sprayer boom movements is an important parameter for the simulation of repartition generated by a sprayer in the dynamic environment of agricultural fields. The existing methods were unsatisfactory for diverse reasons as limited measurement length or insufficient accuracy. Two different sensor data fusion methods were evaluated as input for a model aimed at predicting longitudinal spray deposit. A combination of radar and two accelerometers measurements was found more suited than laser and radar measurements combined in predicting spray repartition. [less ▲]

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See detailA Soil Mechanical Resistance Sensor For On-Line Application In Precision Agriculture: Soil Strength Mapping And Correlation With Soil Physical Properties
Sirjacobs, Damien ULg; Destain, Marie-France ULg

in Proceedings of the 15th Conference of the International Soil Research Organization (I.S.T.R.O.) (2000, July)

Knowledge of local soil strength variation may permit variation of tillage parameters to produce a more optimal soil structure for root growth and plant development. Soil strength mapping can provide ... [more ▼]

Knowledge of local soil strength variation may permit variation of tillage parameters to produce a more optimal soil structure for root growth and plant development. Soil strength mapping can provide another layer of information in precision agriculture. The aim of this research is to develop a sensor able to measure on-line the local soil strength variations. This sensor is designed as follows: a thin blade penetrates the soil to a specific depth while the machine is moving, a beam transfers the soil-blade forces to a transducer fixed on the machine. The transducer measures then the horizontal and vertical forces and the moment. This paper describes a field experiment performed in a 2 ha field of silt soil (Hesbaye, Belgium). The first objective of this research is to establish a map of soil strength variability of the field. For this purpose, the sensor is pulled through the soil in parallel traverses at 5 m separation by a tractor equiped with a DGPS receiver. The second objective of the experiment is to study relation between measured forces and several measured soil physical parameters. Ten homogeneous plots where identified on the sensor track in order to cover as completely as possible the diversity of soil physical conditions encountered. On the median line of each of those plots, 10 Cone Index penetrometry profiles were measured with a mobile automated penetrometer recorder, soil water content was measured in 5 points, ans soil samples were taken in the center of the plot to determine the following parameters: cohesion and internal friction angle, simple compression resistance, Atterberg's limits, granulometry and pF curves. This experiment allowed the first identification of different soil strength areas in the field investigated. [less ▲]

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See detailOn-line fruit grading according to external quality using machine vision.
Leemans, Vincent ULg; Magein, Hugo ULg; Destain, Marie-France ULg

in AgEng Warwick 2000 - Abstract part 1 - Agricultural engineering into the third millennium (2000, July)

This paper presents apple grading into four classes according to European standards. Two varieties were tested, the Golden delicious and the Jonagold. The image database included more than thousand images ... [more ▼]

This paper presents apple grading into four classes according to European standards. Two varieties were tested, the Golden delicious and the Jonagold. The image database included more than thousand images of fruits (528 Golden, 642 Jonagold) belonging to three categories Extra, I, II and to reject. The image grading was achieved in six steps : the image acquisition, the ground colour classification, the defect segmentation, the calyx and stem recognition, the defects characterisation and finally the fruit classification in quality classes. The proposed method for apple external quality grading showed correct classification rates of 78 and 72% respectively for Golden delicious and for Jonagold apples. Taking into account that the healthy fruits were far better graded and considering that this class was under represented, the results of the proposed method (an error rate reaching respectively 5 and 10%) are compatible with the requirements of the European standards. [less ▲]

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See detailLa résistance mécanique du sol: mesure en continu et cartographie pour l’agriculture de précision
Sirjacobs, Damien ULg; Destain, Marie-France ULg

in Zwaenepoel, Philippe (Ed.) Agriculture de Précision - Avancées de la recherche technologique et industrielle (2000, May)

La résistance mécanique d'un sol est un paramètre important qui conditionne la croissance racinaire et le développement des plantes. L'objectif de cette recherche est de mettre au point un capteur capable ... [more ▼]

La résistance mécanique d'un sol est un paramètre important qui conditionne la croissance racinaire et le développement des plantes. L'objectif de cette recherche est de mettre au point un capteur capable de mesurer en ligne les variations locales de résistance du sol. Celui-ci est constitué d'un anneau dynamométrique qui enregistre automatiquement les sollicitations (forces horizontales, verticales et couple) générées par la traction uniforme d'un lame dans le sol. Une première expérience a été menée dans un champ limoneux situé en Hesbaye (Belgique). Le géocodage de ces informations via un système DGPS a permis d'identifier des zones de diverses résistance au sein de la parcelle étudiée. [less ▲]

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See detailAutomatisation d'un banc de répartition pour buses de pulvérisation
Lebeau, Frédéric ULg; Hamza, Elies; Destain, Marie-France ULg

in Cahiers Agricultures (2000)

Les bancs de répartition constituent l'élement de base permettant de tester la sensibilité de la distribution transversale des buses de pulvérisation aux différents paramètres de fonctionnement. L'article ... [more ▼]

Les bancs de répartition constituent l'élement de base permettant de tester la sensibilité de la distribution transversale des buses de pulvérisation aux différents paramètres de fonctionnement. L'article présente un banc d'essai conforme à la norme ISO 5682/1 qui permet une lecture automatisée des différentes grandeurs (pression, débit, volume recueilli). [less ▲]

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See detailQuality fruit grading by colour machine vision: defect recognition.
Leemans, Vincent ULg; Destain, Marie-France ULg; Magein, Hugo ULg

in Acta Horticulturae (2000), (517), 405-412

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See detailDefect segmentation on 'Jonagold' apples using colour vision and a Bayesian classification method
Leemans, Vincent ULg; Magein, Hugo ULg; Destain, Marie-France ULg

in Computers & Electronics in Agriculture (1999), 23(1), 43-53

This paper shows how the information enclosed in a colour image of a bi-colour apple can be used to segment defects. A method to segment pixels, based on a Bayesian classification process, is proposed ... [more ▼]

This paper shows how the information enclosed in a colour image of a bi-colour apple can be used to segment defects. A method to segment pixels, based on a Bayesian classification process, is proposed. The colour frequency distributions of the healthy tissue and of the defects were used to estimate the probability distribution of each class. The results showed that most defects, namely bitter pit, fungi attack, scar tissue, frost damages, bruises, insect attack and scab, are segmented. However, russet was sometimes confused with the transition area between ground and blush colour. (C) 1999 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailLa vision artificielle et la qualité externe des produits agricoles et agro-alimentaires
Leemans, Vincent ULg; Destain, Marie-France ULg

in Application de systèmes optoélectroniques pour le contrôle en ligne des produits agroalimentaires (1998, June 03)

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See detailApplication of neural networks in quality control of 'Jonagold' apples
Leemans, Vincent ULg; Bieuvelet, Frédéric; Destain, Marie-France ULg

in Bellon-Maurel, Véronique (Ed.) Sensoral 98 - International workshop on sensing quality of agricultural products (1998, February)

This paper studies the possibilities to grade the 'Jonagold', a bicolour apple, using neural networks and Fisher"s linear discriminant analysis. In a first step the pixels are sorted into three areas, the ... [more ▼]

This paper studies the possibilities to grade the 'Jonagold', a bicolour apple, using neural networks and Fisher"s linear discriminant analysis. In a first step the pixels are sorted into three areas, the blush colour area, the intermediate colour area and the ground colour area; the accuracy reached 95% with the neural networks. Int the second step the fruit are graded into four categories on their ground colour basis; the accuracy reached 68%whatever the method used. It si also shown that there is no need to separate the ground colour and the intermediate colour to compute the ground colour classification parameters. [less ▲]

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See detailDefects segmentation on 'Golden Delicious' apples by using colour machine vision
Leemans, Vincent ULg; Magein, Hugo ULg; Destain, Marie-France ULg

in Computers & Electronics in Agriculture (1998), 20(2), 117-130

A method based on colour information is proposed to detect defects on 'Golden Delicious' apples. In a first step, a colour model based on the variability of the normal colour is described. To segment the ... [more ▼]

A method based on colour information is proposed to detect defects on 'Golden Delicious' apples. In a first step, a colour model based on the variability of the normal colour is described. To segment the defects, each pixel of ail apple image is compared with the model. If it matches the pixel, it is considered as belonging to healthy tissue, otherwise as a defect. Two other steps refine the segmentation, using either parameters computed on the whole fruit, or values computed locally. Some results are shown and discussed. The algorithm is able to segment a wide range of defects. (C) 1998 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailContrôle de la qualité des pommes par vision artificielle.
Leemans, Vincent ULg; Magein, Hugo ULg; Destain, Marie-France ULg

in Fruit Belge (1998), 66(471),

Article de vulgarisation à destination des profesionnels du secteur fruitier, présentant les possibilités de l'analyse d'images numériques pour le tri des fruits suivant leur qualité externe

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See detailL'automatisation dans l'agriculture et dans l'industrie agro-alimentaire. Un exemple : le tri des fruits en fonction de leurs caractéristiques externes
Leemans, Vincent ULg; Destain, Marie-France ULg

Scientific conference (1997, May 15)

Séminaire de vulgarisation sur l'utilisation des techniques d'analyse d'image pour l'évaluation de la forme de fruit et pour la recherche de défauts.

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See detailApple Shape Inspection with Computer Vision
Leemans, Vincent ULg; Magein, Hugo ULg; Destain, Marie-France ULg

in Sensors for Nondestructive Testing - Measuring the Quality of Fresh Fruits and Vegetables (1997, February)

Two shape separation methods were compared for shape grading of 'Golden Delicious' apples using machine vision. The first one was based on moments and other geometric parameters while the second implied ... [more ▼]

Two shape separation methods were compared for shape grading of 'Golden Delicious' apples using machine vision. The first one was based on moments and other geometric parameters while the second implied the computation of Fourier descriptors.Both methods required that one stem view and six cheek views of the fruit were presented to the camera. The Fourier descriptors were found the most efficient method since they allowed an accuracy in classification reaching 96% and can be made invariant to translation, rotation and scale. Furthermore, they are obtained from boundary information and do not need to examine the whole area of the apple. They permit the reconstruction of the apple shape from the harmonics. [less ▲]

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See detailVision artificielle et quantification de la forme de pommes
Leemans, Vincent ULg; Magein, Hugo ULg; Destain, Marie-France ULg

in Cahiers Agricultures (1997), 6

Golden delicious apples were characterised automatically by machine vision, taking into account six view of the cheeks and one of the stem end. The Fourier transform of the fruit boundaries were computed ... [more ▼]

Golden delicious apples were characterised automatically by machine vision, taking into account six view of the cheeks and one of the stem end. The Fourier transform of the fruit boundaries were computed and normalised. All the relevant information about the shape was included in the first fifteen harmonics. Moreover, particular harmonics were found to characterise the shape of the Golden delicious variety. By using the amplitude of particular harmonics in a discriminant analysis, apple were sorted into categories defined by EU, with a precision around 96%. The proposed method may also be used to compare varieties objectively, in order to identify relation between physiology and shape. [less ▲]

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See detailAction des machines de travail du sol et structure du sol.
Destain, Marie-France ULg

in Pirot, Roland (Ed.) Le travail du sol dans les systèmes mécanisés tropicaux (1997)

Pour analyser l'action des machines de travail du sol, il faut disposer de techniques permettant de quantifier la structure du sol et le microrelief. Dans cet article, la porosité structurale est mesurée ... [more ▼]

Pour analyser l'action des machines de travail du sol, il faut disposer de techniques permettant de quantifier la structure du sol et le microrelief. Dans cet article, la porosité structurale est mesurée en imprégnant d'un mélange résine-colorant des échantillons de sol prélevés de manière non destructive. Une fois les échantillons séchés, la répartition de la porosité est étudiée par analyse d'images et il apparaît que la distribution de fréquence des pores en taille et en forme est caractéristique des façons culturales. Par ailleurs, le microrelief du sol est mesuré à l'aide d'un capteur laser et les données 'hauteur' sont interprétées par analyse de Fourier. La densité spectrale énergétique et la fonction d'autocorrélation rendent très bien compte de l'évolution différenciée du microrelief créé par différents travaux culturaux [less ▲]

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